Method and system for supplying a cleaning gas into a process chamber

ABSTRACT

A method and apparatus for cleaning a process chamber are provided. In one embodiment, a process chamber is provided that includes a remote plasma source and a process chamber having at least two processing regions. Each processing region includes a substrate support assembly disposed in the processing region, a gas distribution system configured to provide gas into the processing region above the substrate support assembly, and a gas passage configured to provide gas into the processing region below the substrate support assembly. A first gas conduit is configured to flow a cleaning agent from the remote plasma source through the gas distribution assembly in each processing region while a second gas conduit is configured to divert a portion of the cleaning agent from the first gas conduit to the gas passage of each processing region.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.14/087,671, filed Nov. 22, 2013, which is a continuation of co-pendingU.S. patent application Ser. No. 13/676,820, filed Nov. 14, 2012 andissued as U.S. Pat. No. 8,591,699, which is a continuation of U.S.patent application Ser. No. 12/571,677, filed Oct. 1, 2009, nowabandoned, which is a divisional application of U.S. patent applicationSer. No. 12/142,402, filed Jun. 19, 2008 and issued as U.S. Pat. No.7,699,935. Each of the aforementioned applications is hereinincorporated by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

Embodiments of the invention generally relate to apparatuses and methodsfor cleaning process chambers of substrate processing apparatuses. Moreparticularly, embodiments of the present invention relate to apparatusand methods for cleaning a process chamber used for deposition.

Description of the Related Art

After a number of deposition steps have been performed in a processchamber, the process chamber may need cleaning to remove undesirabledeposition residues that may have formed on the chamber wall. Oneconventional approach for cleaning current chemical vapor deposition(CVD) or plasma enhanced chemical vapor deposition (PECVD) processchambers is to use cleaning plasma supplied from a remote plasma source(RPS) separate from the process chamber. The RPS provides the cleaningplasma, usually formed from a fluorine-based cleaning gas, which isflowed into the deposition chamber via gas circulation hardwarecomprising a gas box, gas manifold, and a gas distribution systeminstalled in the process chamber.

To obtain a higher etching rate during cleaning, the cleaning plasma isusually supplied in an active form comprised of atomic fluorineradicals. However, complex transport paths from the RPS to thedeposition chamber usually results in a premature recombination of theatomic fluorine radicals into molecular gases that have a lower etchingrate. Consequently, cleaning efficiency may be low even if precursordissociation efficiency of cleaning gases is high. Further, for chambershaving large volume and intricate geometry, such as a 300 mm processchamber, the chamber pumping port is usually close to a shower headutilized to deliver cleaning gases to the chamber. Therefore, poorcirculation of gases under a substrate support assembly positionedbetween the showerhead and pumping port results in decreased cleaningefficiency under the substrate support assembly.

Therefore, there is a need for an improved apparatus and method forcleaning a deposition chamber.

SUMMARY OF THE INVENTION

A method and apparatus for cleaning a process chamber are provided. Inone embodiment, a process chamber is provided that includes a remoteplasma source and a process chamber having at least two processingregions. Each processing region includes a substrate support assemblydisposed in the processing region, a gas distribution system configuredto provide gas into the processing region above the substrate supportassembly, and a gas passage configured to provide gas into theprocessing region below the substrate support assembly. A first gasconduit is configured to flow a cleaning agent from the remote plasmasource through the gas distribution assembly in each processing regionwhile a second gas conduit is configured to divert a portion of thecleaning agent from the first gas conduit to the gas passage of eachprocessing region.

In another embodiment, a substrate processing system is provided thatincludes a loadlock chamber, a transfer chamber coupled to the loadlockchamber, a remote plasma source, and a process chamber coupled to thetransfer chamber. The process chamber includes a chamber body having atleast a first processing region, a first substrate support assemblydisposed in the first processing region, a first gas distributionassembly coupled to the remote plasma source and configured to providegases from the remote plasma source into first processing region fromabove the substrate support assembly, and a gas passage coupled to theremote plasma source and configured to provide gases from the remoteplasma source into the first processing region from below the substratesupport assembly.

In another embodiment, a method for supplying a processing gas into aprocess chamber is disclosed. The method comprises providing a plasmasource, flowing a first volume cleaning agent from the plasma sourcethrough the top of the process chamber into an interior volume of theprocess chamber, and flowing a second volume of cleaning agent into theinterior volume from below a substrate support assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentinvention can be understood in detail, a more particular description ofthe invention, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

FIG. 1 is a schematic plan view showing one embodiment of a processingsystem having a cleaning system.

FIG. 2 is a schematic cross-sectional view of one embodiment of a twinprocess chamber.

FIG. 3A is a horizontal cross-sectional view illustrating one embodimentof a valve used in the process chamber of FIG. 2.

FIG. 3B is a schematic partial isometric cut-away view illustrating thevalve of FIG. 3A.

FIG. 3C is a cross-sectional view illustrating the valve of FIG. 3A.

FIG. 3D is a partial cross sectional view showing an alternativeembodiment of a valve.

FIG. 3E is a cross sectional view showing one embodiment of a valve.

FIG. 4 is a flowchart of method steps for one embodiment of depositionsequence that may be performed in the process chamber of FIG. 2.

FIG. 5 is an exploded cross-sectional view of another embodiment of aflapper.

FIGS. 6-7 are partial sectional view and a top view of the flapper ofFIG. 5.

FIGS. 8A-8B are top and bottom views of another embodiment of a valvebody.

FIG. 8C is a cross-sectional view of the valve body taken along sectionline 8C-8C of FIG. 8B.

FIG. 8D is a cross-sectional view of the valve body taken along sectionline 8D-8D of FIG. 8C.

FIG. 9 depicts one embodiment of flange support.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in oneembodiment may be beneficially utilized on other embodiments withoutspecific recitation.

DETAILED DESCRIPTION

Embodiments described herein relate to a substrate processing systemthat is operable to perform a plasma process (such as etch, CVD, PECVDand the like) on one or more substrates, and undergo plasma cleaning toremove residues formed during the deposition process. One illustratedexample of the substrate processing system comprises, withoutlimitation, a factory interface, a loadlock chamber, a transfer chamber,and at least one process chamber having two or more processing regionsthat are isolatable from each other and share a common gas supply andcommon exhaust pump. To remove deposition residues from the interior ofthe process chamber, a remote plasma source is operable to generatecleaning plasma that is supplied into the interior of the processchamber from the top and bottom of the process chamber. The interior ofthe process chamber can thereby be cleaned in a more efficient manner.

FIG. 1 is a schematic view showing an embodiment of a substrateprocessing system 100. The substrate processing system 100 comprises afactory interface 110 where substrates are loaded into and unloaded fromat least one loadlock chamber 140, a substrate transfer chamber 170housing a robot 172 for handling substrates, and at least one processchamber 200 connected to the transfer chamber 170. The processingchamber 100 is adapted to accommodate various plasma processes andsupport chamber hardware such as etch, CVD or PECVD processes.

As shown in FIG. 1, the factory interface 110 may include substratecassettes 113 and a substrate-handling robot 115. Each of the cassettes113 contains substrates ready for processing. The substrate-handlingrobot 115 may comprise a substrate mapping system to index thesubstrates in each cassette 113 in preparation for loading thesubstrates into the loadlock chambers 140.

The loadlock chambers 140 provide a vacuum interface between the factoryinterface 110 and the transfer chamber 170. Each loadlock chamber 140may comprise an upper substrate support (not shown) and a lowersubstrate support (not shown) stacked within the loadlock chamber 140.The upper substrate support and the lower substrate support areconfigured to support incoming and outgoing substrates thereon.Substrates may be transferred between the factory interface 110 and theloadlock chamber 140 via a slit valve 146, and between the loadlockchamber 140 and the transfer chamber 170 via a slit valve 148. The uppersubstrate support and lower substrate support may comprise features fortemperature control, such as built-in heater or cooler to heat or coolsubstrates during transferring.

The transfer chamber 170 includes a substrate-handling robot 172operable to transfer substrates between the loadlock chamber 140 and theprocess chamber 200. More specifically, the substrate-handling robot 172may have dual substrate-handling blades 174 suitable to transfer twosubstrates at the same time from one chamber to another. The blades 174may also be configured to move independent each other. Substrates may betransferred between the transfer chamber 170 and the process chamber 200via slit valves 176. The movement of the substrate-handling robot 172may be controlled by a motor drive system (not shown), which may includea servo or stepper motor.

FIG. 2 is a schematic cross-sectional view illustrating one embodimentof the process chamber 200. The process chamber 200 comprises twoprocessing regions 202 in which substrates 204 can undergo plasmaprocessing in a concurrent manner. Each processing region 202 hassidewalls 212 and a bottom 214 that partially define a process volume216. The process volume 216 may be accessed through an access port (notshown) formed in the walls 212 as selectively sealed by valves 176 thatfacilitate movement of the substrate 204 into and out of each processingregion 202. The walls 212 and bottom 214 of each processing region 202may be fabricated from a unitary block of aluminum or other materialcompatible with processing. The walls 212 of each processing region 202support a lid assembly 222, and also include the assembly of a liner 224having an exhaust port 226 through which the processing region 202 maybe evacuated uniformly by a vacuum pump (not shown).

A substrate support assembly 230 is centrally disposed within eachprocessing region 202. In one embodiment, the support assembly 230 maybe temperature controlled. The support assembly 230 comprises a supportbase 232 made of aluminum that may encapsulate at least one embeddedheater 234 operable to controllably heat the support assembly 230 andthe substrate 204 positioned thereon to a predetermined temperature. Inone embodiment, the support assembly 230 may operate to maintain thesubstrate 204 at a temperature between about 150 degrees Celsius toabout 1000 degrees Celsius, depending on the processing parameters forthe material being processed.

Each support base 232 has an upper side 236 for supporting the substrate204, whereas the lower side of the support base 232 is coupled to a stem238. The stem 238 couples the support assembly 230 to a lift system 240that moves the support assembly 230 vertically between an elevatedprocessing position and a lowered position that facilitates substratetransfer to and from the processing region 202. The stem 238additionally provides a conduit for electrical and thermocouple leadsbetween the support assembly 230 and other components of the chamber200. A bellows 242 may be coupled between the stem 238 and the bottom214 of each processing region 202. The bellows 242 provides a vacuumseal between the process volume 216 and the atmosphere outside eachprocessing region 202 while facilitating vertical movement of thesupport assembly 230.

To facilitate the transfer of the substrate 204, each support base 232also has a plurality of openings 246 through which lift pins 248 aremovably mounted. The lift pins 248 are operable to move between a firstposition and a second position. The first position, shown in FIG. 2,allows the substrate 204 to rest on the upper side 236 of the supportbase 232. The second position (not shown) lifts the substrate 204 abovethe support base 232 so that the substrate 204 can be transferred to thesubstrate-handling robot 172 coming through an access port (not shown).Upward/downward movements of the lift pins 248 may be driven by amovable plate 250.

The lid assembly 222 provides an upper boundary to the process volume216 in each processing region 202. The lid assembly 222 may be removedor opened to service the processing regions 202. In one embodiment, thelid assembly 222 may be fabricated from aluminum.

The lid assembly 222 may include an entry port 260 through which aprocessing gas may be introduced into the processing region 202. Theprocessing gas may comprise deposition (or etch) gases provided from agas source 261, or cleaning plasma provided from a remote plasma source(RSP) 262. A gas distribution assembly 270 may be coupled to an interiorside of the lid assembly 222. The gas distribution assembly 270 includesan annular base plate 272 having a blocker plate 274 disposedintermediate to a faceplate (or shower head) 276. The blocker plate 274provides an even gas distribution to a backside of the faceplate 276. Aprocessing gas supplied via the entry port 260 enters a first hollowvolume 278 partially limited between the annular base plate 272 and theblocker plate 274, and then flows through a plurality of passages 280formed in the blocker plate 274 into a second volume 282 between theblocker plate 274 and the faceplate 276. The processing gas then entersthe process volume 216 from the second volume 282 through a plurality ofpassages 284 formed in the faceplate 276. The faceplate 276 is isolatedfrom the chamber walls 212 and blocker plate 274 (or base plate 272) viaan insulator material 286. The annular base plate 272, blocker plate 274and faceplate 276 may be fabricated from stainless steel, aluminum,anodized aluminum, nickel or other compatible metal alloys cleanablewith a plasma, such as a chlorine based cleaning gas, a fluorine basedcleaning gas, a combination thereof or other selected cleaningchemistry.

To deliver the processing gas to each processing region 202, a gascirculation system is installed between each processing region 202 andthe gas source 261 and RPS 262. The gas circulation system comprisesfirst gas conduits 290 that respectively link the entry port 260 at thetop of each processing region 202 to the gas source 261 and RPS 262, andat least one second gas conduit 294 connected with the first gas conduit290 via a valve 300. The second gas conduit 294 is coupled to one ormore passages 292 that extends downward through the chamber walls andintersects one or more cross-channels 296 that respectively open into abottom portion of each processing region 202. In the embodiment depictedin FIG. 2, separate passages 292, 296 are utilized to couple each region202 separately to the valve 300. It is also contemplated that eachregion 202 may have gas delivery thereto controlled by a separatededicated valve 300 so that the flow of cleaning gas may be deliveredselectively and independently to each region 202, including deliveringcleaning gas to one of the regions 202 and not the other. When acleaning plasma is provided from the RPS 262, the valve 300 can be openso that a portion of the cleaning plasma that is delivered through thetop of each processing region 202 can also be diverted to the bottomportion of each processing region 202. The stagnation of cleaning plasmabelow the substrate support assembly 230 can thereby be substantiallyprevented and the cleaning efficiency to the region below the substratesupport assembly 230 be improved.

FIGS. 3A-3B are horizontal sectional and schematic partial isometricviews illustrating one embodiment of the valve 300. As shown, the valve300 comprises a valve body 330, a flapper 302, a seal cup 304 and acoupling mechanism 308. The valve body 330 may be fabricated from a hightemperature material suitable for use with the cleaning and processchemistries. Examples of suitable materials include aluminum, aluminumoxide, aluminum nitride, sapphire and ceramic, among others. Otherexamples of suitable materials include materials that are resistant tocorrosion from fluorine and oxygen radicals. In one embodiment, thevalve body 330 is fabricated from aluminum. The valve body 330 housesthe flapper 302 which may be selectively rotated to substantiallyprevent flow from passing between an inlet 399 of the valve body 330 anda pair of outlet ports 332. The inlet 399 is configured to be coupled tothe RPS source 262, while the outlet ports 332 are configured to becoupled to the region 202 through the second gas conduit 294 andpassages 292. The inlet 399 and outlet ports 332 may be configured toaccept a fitting suitable for making leak-free connection to theconduits 290, 294.

The actuator portion of the flapper 302 is surrounded by the cup seal304, which is used to securely fix the seal cup 304 to the valve body330. The flapper 302 is divided into an outer body 310 having agenerally cylindrical shape, and a flow-obstructing plate 312 attachedto an opposite side of the outer body 310. In one embodiment, theflapper 302 including the outer body 310 and obstructing plate 312 maybe a single undivided body made of aluminum or other material asmentioned above. The flapper 302 and body 330 are fabricated with closetolerances so that minimal leakage occurs there between. Thus, theflapper 302 and body 330 are designed to eliminate the need for aseparate dynamic seal which may wear and/or be attached by the cleaninggases and/or other species. When in use, the seal cup 304, whichsubstantially encapsulates the outer body 310, is adapted to allowrelative rotation of the flapper 302, and substantially seal the side ofthe flow-obstructing plate 312 corresponding to the interior of the gascirculation system from the outside environment.

The rotation of the flapper 302 is driven via the coupling mechanism308. In one embodiment, the coupling mechanism 308 has a generallyU-shape with two magnetized end portions 318. The magnetized endportions 318 have embedded magnets that are completely enclosed insidethe flapper 302 so that direct contact of the embedded magnet tocorrosive gases is prevented. The coupling mechanism 308 is placed overthe seal cup 304, with the two magnetized end portions 318 respectivelyfacing two opposite poles 320 of a magnet 322 embedded in the outer body310. The magnet 322 may be a permanent magnet and/or an electromagnet.As a gap is present between the seal cup 304 and the coupling mechanism308, the seal cup 304 is protected from high temperature contact withthe coupling mechanism 308. When the coupling mechanism 308 rotates, themagnetic attraction between the magnetized end portions 318 and theopposite poles 320 of the magnet 322 causes the flapper 302 to rotate.In this manner, the orientation of the flow-obstructing plate 312 can bechanged by rotation to either allow gas flow passage (open state, asshown in FIG. 3A) or block gas flow passage (closed state, as shown inphantom in FIG. 3A).

FIG. 3C is a cross-sectional view showing one embodiment of the valve300 coupled to the second conduit 294 taken along section line C-C ofFIG. 3A. The cup seal 304 includes a collar 306 which may be fastened tothe valve body 330 to retain the flapper 302. A static seal 314 may beprovided between the valve body 330 and collar 306 to prevent leakage.The static seal 314 may be fabricated from a material suitable for usewith the process and cleaning chemistries, which in embodiment utilizingfluorine-based cleaning gases, may be VITON. Since the valve 300 has nomoving, shaft or dynamic seals, the service life of the valve is greatlyextended over conventional designs, and can be operated at temperaturesabove 250 degrees Celsius with substantially no corrosion of the valvecomponents.

The rotation of the flapper 302 may be facilitated via a ball bearing334 that interfaces between an end of the flow-obstructing plate 312 anda wall 335 of the valve body 330, and ball bearing 336 that interfacesbetween the outer body 310 to the seal cup 304. Driven via the couplingmechanism 308, the orientation of the flow-obstructing plate 312 canthereby be oriented to either block or permit the passage of an incidentgas flow 340, such as the cleaning gas being directed into the secondgas conduit 294.

Alternatively, or in addition to the ball bearings 334, 336, a bearing398 may be disposed between the flapper 302 and the valve body 330 asshown in FIG. 3D. The bearing 398 may be fabricated materials that areresistant to corrosion from fluorine and oxygen radicals, which in oneembodiment is a ceramic material. The bearing 398 includes an upper race395 that rotates on a lower race 397 via a plurality of roller 396. Theupper race 395 is in contact with the flapper 302. In one embodiment,the upper race 395 is press-fit to the flapper 302. The lower race 397is in contact with the valve body 330. In one embodiment, the lower race397 is press-fit to the valve body 330. The rollers 396 may have acylinder, ball, tapered, conical or other suitable shape.

Alternatively, one or more magnetic bearings may be utilized to providea bearing between the flapper 302 and the valve body 330 as shown inFIG. 3E. The magnetic bearing includes a pair of repelling magnets. Inthe embodiment depicted in FIG. 3E, the magnetic bearing includes twopair of repelling magnets, a first pair 392A, 394A and a second pair392B, 394B disposed at opposite ends of the flapper 302. The magnets394A, 394B are encapsulated with in the flapper 302 so that they areprotected from the fluorine and oxygen radicals present in the cleaninggases. The magnets 392A, 392B may be permanent magnets orelectromagnets. The magnets pair 392A, 394A and 392B, 394B function tolevitate the flapper 302 within the valve body 330 so that the flapper302 may be freely rotated by the magnetic interaction with the couplingmechanism 308.

The coupling mechanism 308 rotated by an actuator 390 to open and closethe valve 300. The actuator 390 may be a solenoid, air motor, electricmotor, pneumatic cylinder or other actuator suitable for controlling therotary motion of the coupling mechanism 308. The actuator 390 may bemounted to the valve 300, process chamber 200 or other suitablestructure.

FIG. 4 is a flowchart illustrating method steps of one embodiment of asequence for operating the process chamber 200. In initial step 402, asubstrate is introduced in a processing region 202 of the processchamber 200 to undergo a plasma process, such as an etch or depositionprocess. In step 404, while the valve 300 is closed, a process gas isdelivered from the gas source 261 into the process volume 216 throughthe first conduit 290 and the gas distribution plate assembly 270 at thetop of each processing region 202. In step 406, after the plasma processis completed, the substrate is removed out of the processing region 202.In step 408, while the valve 300 is in a closed state, a cleaning agentfrom the RPS 262, such as a chlorine based cleaning gas, a fluorinebased cleaning gas, or a combination thereof, is delivered through thefirst conduit 290 and the gas distribution plate assembly 270 at the topof each processing region 202. In one embodiment, the cleaning gas maycomprise at least one of NF₃, F₂, SF₆, Cl₂, CF₄, C₂F₆, CCl₄ or C₂Cl₆.While the cleaning gas is introduced through the top of each processingregion 202, the valve 300 in step 410 is opened for a period of time todivert a portion of the supplied cleaning plasma through the passages292 to the bottom 214 of each processing region 202 below the substratesupport assembly 230. This additional flow of cleaning plasma reducesthe recombination of fluorine radicals, and eliminates the flowstagnation under the support assembly 230. Moreover, the introduction ofthe diverted cleaning gas through the channels 196 creates a well-mixedturbulent flow below the substrate support assembly 230 prior to beingpumped out of the chamber 200. As a result, the cleaning rate in eachprocessing region 202 may be improved. It is contemplated that theopening of the valve 300 in step 410 may occur prior to orsimultaneously with the introduction of the cleaning gas at step 408. Instep 412, once the cleaning operation is completed, the supply ofcleaning gas is terminated. It is also contemplated that the valve 300may be another type of valve suitable for controlling the relative flowsthrough the conduits 290, 294 from the RPS source 262, includingswitching between the flows through the conduits 290, 294 between flowand no-flow conditions, or providing a range of selected flow ratiosthrough the conduits 290, 294.

As has been described above, the substrate processing system is thusable to controllably flow processing gases through both the top andbottom of a process chamber. During cleaning, the controlled supply of acleaning plasma concurrently through the top and bottom of the processchamber into the process volume (i.e., from both the top and bottomsides of the substrate support) can decrease the recombination ofchemical radicals inside the process volume. The horizontal introductionof the cleaning gas below the support assembly produces a turbulent flowwhich enhances chamber cleaning. Further, lower total mass flow ratecauses a higher weight percentage of cleaning agents to flow into thebottom of the processing chamber. For example, 42.67 mass percentage ofcleaning agent may be directed to the bottom of the processing chamberthrough the conduit 294 and passages 292 under a total plasma flow rateat 5000 sccm while only 28.8 mass percentage of cleaning agent flows tothe bottom of the processing chamber under a total plasma flow rate at15,000 sccm. As a result, lower total plasma flow rate can divert morepercentage of the cleaning agent to the bottom of the process chamber,and thus the process chamber can be cleaned more efficiently.

FIG. 5 is an exploded view of another embodiment of a flapper 500. FIG.6 is a top view of the flapper 500. Referring to both FIGS. 5-6, theflapper 500 includes a body 502, a cap 504 and one or more magnets 506.flapper 302 including the outer body 310 and obstructing plate 312 maybe a single undivided body made of aluminum or other material asmentioned above. The body 502 and cap 504 may be fabricated from thematerials described above.

The body 502 includes outer body 534 and an obstructing plate 538. Theouter body 534 has recess 528 formed in a first end 530 that is sized toreceive at least a portion of the cap 504. In one embodiment, the cap504 is pressed fit into the recess 528 so the cap 504 cannot rotatewithin the recess 528. Alternatively, the cap 504 may be pinned,adhered, bonded, welded or otherwise fastened to the body 502 in amanner that prevents rotation.

The obstructing plate 538 extends from a second end 540 of the body 502to a disk 536. The disk 536 is sized to interface with a recess formedin the valve body to facilitate rotation of the flapper 500. The disk536 generally has a diameter less than a diameter of the outer body 534.A bottom surface 532 of the disk 536 includes pocket 520 for retaining aball bearing (not shown) that facilitates rotation of the flapper 500.

The second end 540 of the body 502 also includes a plurality ofdepressions 542 formed therein. In one embodiment, the depressions 542are radially orientated and equally spaced about a polar array. Thedepressions 542 are configured to mate with projections (not shown)extending from upper race 395 so that the race 395 is locked in rotationwith the flapper 500.

FIG. 7 is a partial sectional view of the disk 536 through the pocket520. The pocket 520 includes a blind hole 606 that is formed concentricto the centerline of the body 502. A countersink 604 is formedconcentric with the hole 606. The countersink 604 is formed at an angle602 that facilitates retention of the ball bearing within the pocket520.

Returning to FIGS. 5-6, the cap 504 includes a cylindrical body 510having an upper end 516 and a lower end 518. The cylindrical body 510has a diameter that fits within the recess 528 of the body 502. A lip508 formed at the upper end 516 of the body 510 so that the end 530 ofthe body 502 seats on a ledge 512 defined by the lip 508, therebysetting the penetration of the body 510 into the body 502 at apredetermined depth. A pocket 520 may also be formed in the cap 504 tofacilitate retention of a ball bearing (not shown) on the center axis ofthe flapper 500.

A cross-hole 514 is formed through the body 510 to receive the one ormore magnets 506. The cross-hole 514 is formed perpendicular to acenterline of the flapper 500. The one or more magnets 506 are capturedin the cross-hole 514 when the cap 504 is inserted into the recess 528of the body 502.

In one embodiment, the one or more magnets 506 include a plurality ofmagnets stacked in a linear arrangement. In the embodiment of FIG. 5,the one or more magnets 506 include a North pole 522, a South pole 524and one more magnets 526 stacked therebetween.

FIGS. 8A-8B are top and bottom views of another embodiment of a valvebody 800. The valve body 800 is generally a unitary aluminum or ceramicmember, although the valve body 800 may be fabricated from othersuitable materials. The valve body 800 includes a top surface 802 and abottom surface 804. A first bore 810 is formed into the body 800 fromthe top surface 802. The first bore 810 is positioned at least partiallyin an extending portion 806. The extending portion 806 has a firstpassage 812 (shown in phantom) formed therethrough. The end of the firstpassage 812 servers to connect the valve body 800 to the conduitsleading to the remote plasma source 262. The second end of the firstpassage 812 is tied into a second passage 824 (also shown in phantom).The first bore 810 is aligned with the first passage 812 and is sized toreceive the flapper as to control the flow of fluid through the firstpassage 812 to the second passage 824. A plurality of threaded blindmounting holes 816 are formed in the first side 802 of the valve body800 to retain the seal cup (not shown) to the valve body 800.

The second side 804 of the valve body 800 includes a second and thirdbores 818. The second and third bores 818 communicate with the secondpassage 824 on either side of intersection of the first and secondpassages 812, 824. An o-ring groove 820 circumscribes each bore 818 toallow the conduits extending from the valve 800 into the chamber body tobe sealingly coupled to the valve 800. The o-rings may be compressed toseal a fitting coupled to the second and third bores 818 using fasteners(not shown) passed through mounting holes 822 formed through the body800. In the embodiment depicted in FIGS. 8A-8B, four mounting holes 822are associated with each bore 818.

Referring now to the sectional view of FIG. 8C, the second passage 824may be sealed at either end by plugs 830. The plugs 830 may be pressedfit, welded, bonded, adhered, threaded or sealingly coupled to the body800 by another suitable manner.

Referring now to the sectional view of FIG. 8D, the first bore 810include a ledge 832 that interfaces with the outer body of the flapperand/or supports the lower race 397 of the bearing 398. The obstructingplate of the flapper extends into the bore 810 and may be rotated as tocontrol the flow through the first passage 812. The bottom of the firstbore 810 may also include a pocket 520 to facilitate retention of theball (not shown) disposed between the flapper and the body 800. Inembodiments wherein a bearing 398 is utilized, the ledge 832 may includea plurality of depressions 840 that are configured to mate withprojections extending from the lower race 397 of the bearing 398 suchthat the lower race 397 is fixed to the body 800 while the flapper 500rotates.

Returning to FIG. 1, a flange support 299 is coupled in line with theoutlet of the remote plasma source 262 to allow a pressure sensor 297 todetect a metric indicative of the output pressure of the remote plasmasource 262. The sensor 297 may be in the form of a manometer, pressuregage or other sensor suitable for obtaining a metric indicative of thepressure of the cleaning agent exiting the remote plasma source 262.

FIG. 9 depicts one embodiment of flange support 299. The flange support299 includes an inlet 902 and two outlets 904, 906. The inlet 902 iscoupled to the outlet of the remote plasma source 262 and fluidlycoupled to the first outlet 904 through a main passage 920 extendingthrough the flange support 299. The first outlet 904 is coupled to theconduit that provides the cleaning agent from the remote plasma source262 to the valve 300 and entry ports 260. The second outlet 906 isfluidly coupled to the main passage 920 coupling the inlet 902 to thefirst outlet 904 by a secondary passage 922. The second outlet 906 isconfigured to accept the sensor 297.

In one embodiment, the flange support 299 includes a flange base 912, apipe 914, an elbow 916 and a flange 918 which are assembled as apressure tight assembly. In one embodiment, the flange base 912, pipe914, elbow 916 and flange 918 are fabricated from aluminum or stainlesssteel and are welded together, for example, by a continuous weld. Theflange base 912 includes a cylindrical body 926 through which the mainpassage 920 is formed. The cylindrical body 926 has a major flange 928at a first end and a minor flange 930 through a second end.

The inlet 902 is formed through the minor flange 930 and iscircumscribed by an o-ring groove 932 on its face 934. The face 934 ofthe minor flange 930 also includes a plurality of mounting holes, notshown, which is one embodiment are in the form of a plurality of throughholes.

The first outlet 904 is formed through the major flange 928. A face 936of the major flange 928 is finished to provide a sealing surface. Theface 936 of the major flange 928 also includes a plurality of mountingholes, not shown, which is one embodiment are in the form of a pluralityof through holes.

The cylindrical body 926 includes a hole 938 which breaks into the mainpassage 920. In one embodiment the hole 938 is formed substantiallyperpendicular to the centerline of the body 926, which is coaxial withthe centerline of the main passage 920.

The pipe 914 is configured to sealing couple to the cylindrical body 926in a manner that fluidly coupled a passage 940 defined through the pipe914 with the hole 938. In one embodiment, a first end of the pipe 914has a taper or has a reduced outside diameter that is inserted into thehole 938 to facilitate coupling of the pipe 914 to the body 926. Thesecond end of the pipe 914 may have a taper or has a reduced outsidediameter that is inserted into the elbow 916 to facilitate coupling ofthe pipe 914 to the elbow 916.

The flange 918 includes a cylindrical stem 950 having a passage 960formed therethrough. One end of the stem 950 has a lip 952. The lip 952circumscribes a port 954 that defines the second outlet 906. The port954 is configured in manner suitable for coupling the sensor 297 to theflange support 299.

In one embodiment, a face 956 of the lip 952 includes a recess 958 whichis concentric with the passage 960 through the stem 950. The face 956 ofthe lip 952 may have an orientation substantially perpendicular to thecenterline of the passage 960. A backside 962 of the lip 952 may betapered to facilitate coupling a fitting, not show, utilized to securethe sensor 297. In one embodiment, the backside of the lip forms anangle with the stem of about 205 degrees. The passage 960 formed throughthe flange 918, a passage 964 formed through the elbow 916, the passage940 formed through the pipe 914 and the hole 938 formed in the supportflange 912 define the secondary passage 922.

Thus, the flange support 299 allows direct delivery of the cleaningagents from the remote plasma source 262 with minimal obstruction whichwould adversely promote recombination. Additionally, the flange support299 facilitates coupling of the sensor 297 in a convenient location thatis remote from the other utilities routed to the top of the chamber.

While the foregoing is directed to certain embodiments of the presentinvention, other and further embodiments of the invention may be devisedwithout departing from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

What is claimed is:
 1. A valve for selectively controlling flow betweena first gas conduit and a second gas conduit, comprising: a valve body;a first magnet encased in the valve body; a movable flapper housed bythe valve body, wherein the flapper comprises: a flow-obstructing plate;an outer body attached to the flow-obstructing plate, the outer bodyincluding a first end and a second end; and a second magnet encased inthe flapper, wherein, the flow obstructing plate extends from the secondend of the outer body, the second end of the outer body including aplurality of depressions formed therein to engage with projections froma bearing disposed between the outer body and the valve body, and thefirst end of the outer body has a recess, a cap is inserted in therecess, the cap including a cross-hole formed perpendicularly to acenterline of the flapper, and one or more drive magnets are captured inthe cross-hole; and a coupling mechanism disposed outside the valve bodyoperable to rotate the outer body and the flow-obstructing plate aboutthe centerline of the flapper so that the flapper rotates between afirst position where the flow-obstructing plate blocks flow through thevalve body and a second position where the flow-obstructing plate allowsflow through the valve body, wherein the first magnet and the secondmagnet form a pair of repelling magnets to levitate the flapper withinthe valve body.
 2. The valve of claim 1, wherein the coupling mechanismis configured to rotate the flapper through magnetic interaction.
 3. Thevalve of claim 1, wherein the first magnet is disposed in a wall of thevalve body, the second magnet is encased in an end of theflow-obstructing plate, and the first and second magnets form a bearinginterfacing between the end of the flow-obstructing plate and the wallof the valve body to facilitate rotation of the flapper.
 4. The valve ofclaim 1, wherein the flow-obstructing plate and the outer body are asingle undivided body.
 5. The valve of claim 4, wherein theflow-obstructing plate and the outer body are made of aluminum.
 6. Thevalve of claim 1, wherein the coupling mechanism includes two magnetizedend portions, and magnetic attraction between the magnetized endportions and opposite poles of the one or more drive magnets causes theflapper to rotate.
 7. The valve of claim 6, wherein the couplingmechanism includes a U-shape body having the two magnetized endportions.
 8. The valve of claim 1, wherein the flow-obstructing platehas a first end connected to the outer body and a second end connectedto a disk.
 9. A valve for selectively controlling flow between a firstgas conduit and a second gas conduit, comprising: a valve body; aflapper housed by the valve body, wherein the flapper is operable torotate about a centerline of the flapper in the valve body between afirst position where the flapper blocks flow through the valve body anda second position where the flapper allows flow through the valve body;a first magnet encased in the valve body; a second magnet encased in theflapper, wherein the first magnet and the second magnet form a pair ofrepelling magnets to levitate the flapper along the centerline withinthe valve body; a coupling mechanism disposed outside the valve body torotate the flapper through magnetic interaction, wherein the flappercomprises: a flow-obstructing plate; and an outer body attached to theflow-obstructing plate, the outer body including a first end and asecond end, wherein the outer body interacts with the couplingmechanism, wherein the flow-obstructing plate extends from the secondend of the outer body, the second end of the outer body includes aplurality of depressions formed therein to engage with projections froma bearing disposed between the outer body and the valve body, the firstend of the outer body has a recess, a cap is inserted in the recess, thecap includes a cross-hole formed perpendicularly to the centerline ofthe flapper, and one or more drive magnets are captured in thecross-hole.
 10. The valve of claim 9, wherein the flow-obstructing plateand the outer body are a single undivided body.
 11. The valve of claim10, wherein the flow-obstructing plate and the outer body are made ofaluminum.
 12. The valve of claim 9, wherein the coupling mechanismincludes two magnetized end portions, and magnetic attraction betweenthe magnetized end portions and opposite poles of the one or more drivemagnets causes the flapper to rotate.
 13. The valve of claim 12, whereinthe coupling mechanism includes a U-shape body having the two magnetizedend portions.
 14. The valve of claim 9, wherein the flow-obstructingplate has a first end connected to the outer body and a second endconnected to a disk.